Resistor ladder networks typically comprise a plurality of resistors and a plurality of switches disposed such that closing any one of the switches alters either the high resistance or the low resistance of a voltage divider circuit. The voltage divider circuit is comprised of a high resistance between a supply voltage and an output terminal and a low resistance between the output terminal and a low voltage reference. The resistor ladder is substituted for either the high resistance or low resistance in the voltage divider network. In this way, the resistance of the network is a variable and will exhibit a unique resistance range depending upon the selected state of the switch. Thus, the output voltage of the voltage divider is indicative of that, if any, of the switches are closed (e.g., user switch selection). Resistor ladder networks are increasingly used in vehicular applications due to their flexibility of implementation and cost savings.
In certain vehicular applications, more than one electronic module receiver may require knowledge from a particular switch state. For example, in hybrid vehicles, a hybrid control module may use a hood state (e.g., whether the hood of the vehicle is open or closed) in order to disable a high voltage source for safety. In addition, a body control module may simultaneously use the hood state for theft deterrent and remote start functions.
One possible solution is to have the first module read the respective switch state, and then transmit the state over a data bus to the second module. An alternative solution may involve the use of duplicate switches or switching networks (e.g., one switch or switching network per electronic module). However, both of these solutions add unneeded cost and complexity.
Accordingly, it is desirable to implement a solution for multiple electronic module receivers without the drawbacks of other solutions described above. In addition, it is desirable to incorporate resistor ladder functionality into such a proposed solution. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.